The invention relates to a sewing machine with an automatic buttonhole stitching device, and more particularly to a device which includes a plurality of pattern cams for producing stitches in each of the steps in stitching a buttonhole, and a member for storing the number of stitches with an electronic control device.
The stitches are formed in sequence formed by selecting a pattern cam from the plurality of cams by a pattern selecting operation, designating memory in advance, and storing the number of stitches having been formed in each of the stitching steps of the buttonhole. Subsequent or following buttonholes are formed in succession with the number of stored stitches, is that a plurality of buttonholes of the same size are automatically produced.
Generally, this kind of the buttonhole stitching is performed with a pattern selecting operation, e.g., 4 steps. In the 1st step pattern is selected, and a right line-track of a determined length is formed on a fabric to be sewn. A bar-tack is selected in the 2nd step, and is formed with the number of stitches. In the 3rd step a left line-track is selected and is formed to be of the same length as that of the right line-tack previously formed. Finally, as a 4th step a bar-tack is selected and is formed with the number of stitches. Thus, one buttonhole is completed. A buttonhole of the same size is in succession formed through the same operation as said. However, formation of a plurality of buttonholes of the same size has not been easy in the prior art.